scholarly journals Biological properties of bone marrow plasma cells influence their recovery in aspirate specimens: impact on classification of plasma cell disorders and potential bias to evaluation of treatment response

2020 ◽  
Vol 99 (11) ◽  
pp. 2599-2609
Author(s):  
Svitlana Demyanets ◽  
Alexandra Kaider ◽  
Ingrid Simonitsch-Klupp ◽  
Günther Bayer ◽  
Almira Subasic ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Plasma Cell ◽  
Plasma Cells ◽  
Cell Phenotype ◽  
Special Focus ◽  
Plasma Cell Disorders ◽  
Bone Marrow Plasma ◽  
The Impact

Abstract Methods to estimate bone marrow plasma cells (BMPC) basically include histopathology, cytomorphology, and flow cytometry. The present study compares the outcomes of these methods with special focus on the impact of BMPC-specific characteristics on their recovery by either method. Laboratory reports of diagnostic samples from 238 consecutive patients with suspected or known plasma cell disease were retrospectively analyzed. The median (IQR) proportion of BMPC was 30.0% (15.0–70.0%) by histological review (hBMPC), 7.0% (2.0–16.0%) by smear review (sBMPC), and 3.0% (0.8–10.0%) by flow cytometry (fBMPC). The disparity of results between core biopsy and aspirate smear was enhanced in case of poor quality of the smear, increased BM fiber content, higher grade cell atypia, expression of CD56 (all P < 0.0001), the number of cytogenetic aberrations (P = 0.0002), and abnormalities of the MYC gene (P = 0.0002). Conversely, expression of CD19 and a non-clonal plasma cell phenotype were associated with a lower difference between hBMPC and sBMPC (both P < 0.0001). The disparity between the percentages of sBMPC and fBMPC was associated with the quality of the smear (P = 0.0007) and expression of CD56 (P < 0.0001). Our results suggest that the recovery of BMPC in aspirate specimens not only is a matter of sampling quality but also depends on biological cell properties. Aspiration failure due to malignant type features of BMPC may lead to misclassification of plasma cell disorders and represent a bias for the detection of minimal residual disease after therapy.

Quantitation of Plasma Cells in Bone Marrow Aspirates by Flow Cytometric Analysis Compared With Morphologic Assessment

2007 ◽  
Vol 131 (6) ◽  
pp. 951-955
Author(s):  
Kristi J. Smock ◽  
Sherrie L. Perkins ◽  
David W. Bahler
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Plasma Cell ◽  
Gold Standard ◽  
Plasma Cells ◽  
Flow Cytometric Analysis ◽  
Flow Cytometric ◽  
Bone Marrow Plasma ◽  
Plasma Cell Dyscrasias ◽  
Cellular Processing

Abstract Context.—Accurate quantitation of bone marrow plasma cells is an important component in the diagnosis and posttreatment assessment of plasma cell dyscrasias. Although flow cytometry is sometimes used for this purpose and can rapidly evaluate many cells, the accuracy of flow-based plasma cell quantitation compared with morphologic assessment (currently the gold standard) is uncertain as direct comparison studies have not been previously reported. Objective.—To determine how percentages of plasma cells in diagnostic aspirate smears quantitated by morphologic assessment relate to percentages of plasma cells quantified by flow cytometry. Design.—Thirty bone marrow cases with 10% or more plasma cells and leukemia/lymphoma flow cytometry immunophenotyping studies were identified from our hematopathology database. The Wright-stained aspirate smears, marrow biopsy sections, and flow cytometry histograms were reviewed. Results.—Morphologically determined plasma cell percentages from the diagnostic aspirate smears were consistently higher than those determined by flow cytometry. Much of this difference appeared to be related to differences in sample quality. However, the cellular processing involved in performing flow cytometry also appeared to reduce plasma cell percentages in many cases. Conclusions.—This study helps define the limitations of flow cytometry for quantitating plasma cell loads in marrow aspirate specimens that may significantly affect the diagnosis or assessment of treatment response.

Rapid and Sensitive Detection of Minimal Plasma Cell Populations Using Six-Colour Flow Cytometry.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3526-3526
Author(s):  
Ruth M. de Tute ◽  
Selina J. Denman ◽  
J. Anthony Child ◽  
Roger G. Owen ◽  
Andy C. Rawstron
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
B Cells ◽  
B Cell ◽  
Plasma Cell ◽  
Plasma Cells ◽  
Residual Disease ◽  
Limit Of Detection ◽  
Cell Phenotype ◽  
High Dose

Abstract Flow cytometry is a powerful tool for diagnosis and detection of minimal residual disease (MRD) in patients with monoclonal gammopathies. Multi-parameter MRD flow analysis is more sensitive than serum immunofixation for the detection of residual disease and is as effective as PCR analysis for predicting outcome after high-dose therapy. Attaining a limit of detection of 0.01% abnormal plasma cells in every patient requires analysis of several neoplastic markers. However, basic immunophenotyping coupled with clonality assessment can be informative in many patients. This approach can also be helpful at diagnosis in MGUS patients to determine whether the primary abnormal component is plasmacytoid or lymphoid. The aim of this study was to develop a single six-colour assay that could be used as a rapid and sensitive screen for the presence of neoplastic plasma cells. Bone marrow aspirate samples were assessed from 83 patients at diagnosis with a suspected plasma cell disorder (median age 69.1 years, 48 male and 35 female) and from 62 patients with myeloma after treatment (median age 61.0 years, 40 male and 22 female). Cells were washed and surface-labelled with CD19 PE, CD38 PE-Cy7, CD138 APC and CD45 APC-Cy7 then fixed, permeabilised and incubated with Kappa FITC and Lambda PE-Cy5. The assay allows assessment of B-cell surface-Ig and plasma cell cytoplasmic-Ig light chain restriction and abnormal plasma cell phenotype according to CD19 and CD45 expression. In presentation cases with more than 10% plasma cells by morphology, neoplastic plasma cells were present in 48/50 samples with one reactive plasmacytosis (32% plasma cells) and one patient with Castlemans disease (11% PC). In the remaining 33 cases with <10% plasma cells, 16/33 (48%) had monoclonal plasma cells, 4/33 (12.1%) showed a low-level of monoclonal B-cells and the remainder had normal B-cells and plasma cells. The assay provided a quantitative MRD result in 44/62 (70%) cases: neoplastic plasma cells represented <1% of leucocytes in 26/44 of the samples (59%) and the assay could detect neoplastic plasma cells when they represented as few as 0.01% of total leucocytes in several patients (4/44, 9.1%). Using this screening approach an extended MRD analysis panel was only required in 18/62 (30%) of cases where CD19- plasma cells were detected on a polyclonal background. Marrow quality was compared with a paired trephine biopsy in 68 samples. Using a algorithm based on the levels of normal plasma cells, B-progenitors, nucleated red cells and myeloid progenitors it was possible to determine whether the samples were representative bone marrow and a quantitative result could be provided. This single tube six-colour approach allows simultaneous assessment of B-cell and plasma cell immunophenotype and clonality. The incorporation of all the relevant markers into a single test makes analysis more straightforward and the gating strategy more reproducible. The assay is more rapid and cost-effective than four-colour analysis as fewer total markers are required. It can be applied to presentation samples to exclude reactive plasmacytoses and B-lymphoproliferative disorders, and to follow up samples to reduce the need for further flow cytometric investigations and optimise any downstream testing that is necessary. In approximately 70% of post-treatment myeloma samples this assay is capable of providing a definitive MRD result up to a maximum sensitivity of 0.01%.

scholarly journals Multiple myeloma: circulating lymphocytes that express plasma cell antigens

Blood ◽  
1984 ◽  
Vol 64 (2) ◽  
pp. 352-356
Author(s):  
GJ Ruiz-Arguelles ◽  
JA Katzmann ◽  
PR Greipp ◽  
NJ Gonchoroff ◽  
JP Garton ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Plasma Cell ◽  
Peripheral Blood ◽  
Plasma Cells ◽  
Peripheral Blood Lymphocytes ◽  
Tumor Burden ◽  
B Cell Differentiation ◽  
Blood Lymphocytes ◽  
Bone Marrow Plasma

The bone marrow and peripheral blood of 14 patients with multiple myeloma were studied with murine monoclonal antibodies that identify antigens on plasma cells (R1–3 and OKT10). Peripheral blood lymphocytes expressing plasma cell antigens were found in six cases. Five of these cases expressed the same antigens that were present on the plasma cells in the bone marrow. Patients that showed such peripheral blood involvement were found to have a larger tumor burden and higher bone marrow plasma cell proliferative activity. In some patients, antigens normally found at earlier stages of B cell differentiation (B1, B2, and J5) were expressed by peripheral blood lymphocytes and/or bone marrow plasma cells.

scholarly journals Complement receptors regulate differentiation of bone marrow plasma cell precursors expressing transcription factors Blimp-1 and XBP-1

2005 ◽  
Vol 201 (6) ◽  
pp. 993-1005 ◽  
Author(s):  
Dominique Gatto ◽  
Thomas Pfister ◽  
Andrea Jegerlehner ◽  
Stephen W. Martin ◽  
Manfred Kopf ◽  
...  
Keyword(s):  
Bone Marrow ◽  
B Cells ◽  
B Cell ◽  
Plasma Cell ◽  
Cell Activation ◽  
Plasma Cells ◽  
Antibody Responses ◽  
Complement Receptors ◽  
Essentially Normal ◽  
Bone Marrow Plasma

Humoral immune responses are thought to be enhanced by complement-mediated recruitment of the CD21–CD19–CD81 coreceptor complex into the B cell antigen receptor (BCR) complex, which lowers the threshold of B cell activation and increases the survival and proliferative capacity of responding B cells. To investigate the role of the CD21–CD35 complement receptors in the generation of B cell memory, we analyzed the response against viral particles derived from the bacteriophage Qβ in mice deficient in CD21–CD35 (Cr2−/−). Despite highly efficient induction of early antibody responses and germinal center (GC) reactions to immunization with Qβ, Cr2−/− mice exhibited impaired antibody persistence paralleled by a strongly reduced development of bone marrow plasma cells. Surprisingly, antigen-specific memory B cells were essentially normal in these mice. In the absence of CD21-mediated costimulation, Qβ-specific post-GC B cells failed to induce the transcriptional regulators Blimp-1 and XBP-1 driving plasma cell differentiation, and the antiapoptotic protein Bcl-2, which resulted in failure to generate the precursor population of long-lived plasma cells residing in the bone marrow. These results suggest that complement receptors maintain antibody responses by delivery of differentiation and survival signals to precursors of bone marrow plasma cells.

New Criteria To Identify Risk of Progression in Monoclonal Gammopathy of Uncertain Significance: Multiparametric Flow Cytometry Analysis of Bone Marrow Plasma Cells.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3517-3517
Author(s):  
Ernesto Perez-Persona ◽  
María-Belén Vidriales ◽  
Gema Mateo ◽  
Ramón Garcia Sanz ◽  
Marivi Mateos ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Monoclonal Gammopathy ◽  
Plasma Cells ◽  
Flow Cytometry Analysis ◽  
Dna Index ◽  
Multiparametric Flow Cytometry ◽  
Uncertain Significance ◽  
Risk Of Progression ◽  
Bone Marrow Plasma

Abstract Monoclonal Gammopathy of Uncertain Significance (MGUS) is a monoclonal disorder defined by the presence of a serum monoclonal protein <3g/dL, bone marrow plasma cells < 10% and absence of end-organ damage. The risk of progression to multiple myeloma (MM) is about 1% per year, and therefore these patients require long follow-up. Accordingly, the definition of new parameters that could be used for the identification of patients at risk of progression could be of great value. The aim of the present study is to evaluate the utility of multiparameter flow cytometry analysis of bone marrow (BM) plasma cells (PC) for predicting the risk of progression of MGUS patients. From January 1996 to September 2004, bone marrow aspirate samples from 350 patients, who fulfil the criteria of MGUS according to the International Myeloma Working Group criteria, were analysed by multiparametric flow cytometry. A specific gate on PC was performed based on CD138/CD38 expression and FSC/SSC characteristics and PC were immunophenotypically classified as normal (polyclonal) or aberrant (clonal) according to the expression of CD138, CD38, CD45, CD19 and CD56 antigens. Twenty seven patients (8 %) progressed to MM, with a median time to progression (TTP) of 46 months (range 9 to 109 months). Interestingly, the percentage of aberrant PC within the total BM PC compartment (aPC/BMPCc) clearly identify patients at different risk of progression. Thus, TTP in patients with ≥ 95% aPC/BMPCc was 85 months vs not reached cases with <95% aPC/BMPCc (p=0.0000). Other parameters with a significant influence on progression in the univariate analysis were: paraprotein level (higher vs lower of 2 mg/dl; p= 0.0004), the presence of immunoparesis (no paresis vs. decreased levels in one or two Ig. p= 0.0005), Bence-Jones proteinuria (p= 0.0003), PC BM infiltration assessed both by morphology and flow cytometry (p=0.0074; and p= 0.001, respectively), and DNA index assessed by flow cytometry (diploid vs aneuploid; p=0.0064). Moreover, the cut off level of 95% aPC/BMPCc, also allows the discrimination of two risk categories upon considering only patients at low risk of progression, based on a low paraprotein level or absence of inmunoparesis (p= 0.0000 and p= 0.0000, respectively). On multivariate analysis only the percentage of aPC/BMPCc (≥95%) (p=0.000), the DNA index (p=0.007), and the Bence-Jones proteinuria (p=0.000) showed independent prognostic value. In summary, our results show that multiparameter FC evaluation of BMPC at diagnosis is a simple, cost-effective and valuable tool for predicting the risk of progression of MGUS patients.

Bone Marrow Immunophenotypic Analysis Allows the Identification of High Risk of Progression and Immune Condition-Related Monoclonal Gammopathy of Undetermined Significance.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2804-2804
Author(s):  
AndrÉs Jerez ◽  
Francisco Ortuño ◽  
María del Mar Osma ◽  
Ignacio Español ◽  
Ana Gonzalez ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
High Risk ◽  
Plasma Cells ◽  
Plasma Cell Dyscrasia ◽  
Newly Diagnosed ◽  
Immune Disorders ◽  
Chronic Infections ◽  
Risk Of Progression ◽  
Bone Marrow Plasma

Abstract Abstract 2804 Poster Board II-780 Background: Monoclonal gammopathy of undetermined significance (MGUS) progresses to plasma cell dyscrasia, mainly multiple myeloma (MM), at a rate of approximately 1% per year. Moreover, recent studies have shown that MM is nearly always preceded by MGUS, encouraging investigators to find better predictors for MM development in order to implement strategies to prevent or delay progression. In addition, a high prevalence of MGUS has been noted in a series of patients with immune disorders or chronic infections. Multiparameter flow cytometry allows the identification and quantification of both monoclonal and polyclonal plasma cells. This study analyses the relationship between monoclonal and polyclonal bone marrow plasma cells (BMPC), studied by means of flow cytometry, and its association with either immune or infectious disorders, or the development of MM in newly diagnosed MGUS patients. Methods: We conducted a retrospective cohort study to analyse the prognostic value of the aberrant (CD38++ CD138+ CD19– CD45weak) to normal (CD38++ CD138+ CD19+ CD45+) phenotype bone marrow plasma cells ratio (A/N ratio) and another 13 variables at baseline for the development of a plasma cell dyscrasia. We also performed a cross-sectional study to evaluate the association of those variables at baseline with the presence of a chronic immune response disorder. In each patient, the following variables were examined: age, sex, hemoglobin, serum creatinine, serum calcium, B2-Microglobulin, type and size of the serum monoclonal component (MC), isotype of the MC immunoglobulin, presence of urine MC, quantification of serum immunoglobulin levels, erythrocyte sedimentation rate, BMPC percentage and presence of atypical plasma cells on light microscopy, and aberrant and normal phenotype BMPC percentages. The effect of variables on progression was calculated using a Cox proportional hazards regression model. To identify variables at baseline associated with immune or chronic infectious disorders. a series of univariate and multivariate analyses was fitted using a binary logistic regression strategy. Results: Between March 1997 and April 2008, flow cytometry analysis on bone-marrow samples was performed on 322 patients with newly diagnosed MGUS. Median patient age was 71 years (interquartile range (IQR) 63-78 years) with a slightly male predominance (51%). Median follow-up was 46 months (IQR 23-58 months). During the period of observation, in 23 (7.1%) patients a transformation was registered into: MM (n=22), and primary amyloidosis (n=1). A total of 24 (7.4%) patients had a diagnosis of autoimmune disorder, and 18 (5.6%) patients of a chronic infection. Multivariate analysis for progression to MM revealed an increased A/N ratio as the main independent prognostic variable. In addition, our study found a significant association between a reduced A/N ratio and the diagnosis of a chronic immune response related condition. Using receiver-operating characteristic analysis we created an A/N ratio range from 4 to 0.20. Values of 4 or higher define a group of MGUS patients at high risk of progression (OR, 10.7; 95% confidence interval 4.2-39), whereas A/N ratio values of 0.20 or lower are associated with immune disorders or chronic infections (OR, 20.9; 95% confidence interval 8.5-51.1). A total of 282 patients had an A/N ratio below 4, and 42 had values equal to or above the cut-off. Patients with an A/N ratio ≥ 4 had a cumulative probability of transformation of 35% at 5 years, compared with 3% for those with an A/N ratio < 4. Conclusions: Extreme values of the A/N ratio at diagnosis seem to be related with two different conditions: high risk MGUS, likely to progress to MM, and immune condition related MGUS. Our findings further support the routine use of phenotypic characterization of bone marrow plasma cells in patients with MGUS at diagnosis. Disclosures: No relevant conflicts of interest to declare.

The Natural History of Smoldering (Asymptomatic) Multiple Myeloma.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3396-3396 ◽  
Author(s):  
Robert Kyle ◽  
Ellen Remstein ◽  
Terry Therneau ◽  
Angela Dispenzieri ◽  
Paul Kurtin ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Plasma Cell ◽  
Light Chain ◽  
Plasma Cells ◽  
M Protein ◽  
Cell Content ◽  
Bone Marrow Plasma ◽  
M Spike

Abstract Smoldering multiple myeloma (SMM) is characterized by a serum M protein ≥ 3g/dL and/or 10% or more of plasma cells in the bone marrow. However, the definition is not standardized, and it is not known whether both serum M protein levels and bone marrow plasma cell counts are necessary for diagnosis or if one parameter is sufficient. We reviewed the medical records and bone marrows of all patients from Mayo Clinic seen within 30 days of recognition of an IgG or IgA M protein ≥ 3g/dL or a bone marrow containing ≥ 10% plasma cells from 1970 to 1995. This allows for a minimum potential follow-up of 10 years. Patients with end-organ damage at baseline from plasma cell proliferation, including active multiple myeloma (MM) and primary amyloidosis (AL) and those who had received chemotherapy were excluded. A differential of the bone marrow aspirate coupled with the bone marrow biopsy morphology and immunohistochemistry using antibodies directed against CD138, MUM-1 and Cyclin D1 were evaluated in every case in order to estimate the plasma cell content. In all, 301 patients fulfilled either of the criteria for SMM. Their median age was 64 years and only 3% were less than 40 years of age; 60% were male. The median hemoglobin value was 12.9 g/dL; 7% were less than 10 g/dL, but the anemia was unrelated to plasma cell proliferation. IgG accounted for 75%, IgA 22%, and biclonal proteins were found in 3%. The serum light-chain was κ in 67% and λ in 33%. The median serum M spike was 2.9 g/dL; 11% were at least 4.0 g/dL. Uninvolved serum immunoglobulins were reduced in 81%; only 1 immunoglobulin was reduced in 31% and both were decreased in 50%. The urine contained a monoclonal κ protein in 36% and λ in 18% and 46% were negative. The median size of the urine M spike was 0.04 g/24h; only 5 (3%) were &gt; 1 g/24h. The median bone marrow plasma cell content was 15 – 19%; 10% had less than 10% plasma cells, while 10% had at least 50% plasma cells in the bone marrow. Cyclin D-1 was expressed in 17%. Patients were categorized into 3 groups: Group 1, serum M protein ≥ 3g/dL and bone marrow containing ≥ 10% plasma cells (n= 113, 38%); Group 2, bone marrow plasma cells ≥ 10% but serum M protein &lt; 3g/dL (n= 158, 52%); Group 3, serum M protein ≥ 3g/dL but bone marrow plasma cells &lt; 10% (n= 30, 10%). During 2,204 cumulative years of follow-up 85% died (median follow-up of those still living 10.8 years), 155 (51%) developed MM, while 7 (2%) developed AL. The overall rate of progression at 10 years was 62%; median time to progression was 5.5 yrs. The median time to progression was 2.4, 9.2, and 19 years in groups 1, 2, and 3 respectively; correspondingly at 10 years, progression occurred in 76%, 59%, and 32% respectively. Significant risk factors for progression with univariate analysis were serum M spike ≥ 4g/dL (p &lt; 0.001), presence of IgA (p = 0.003), presence of urine light chain (p = 0.006), presence of λ urinary light chain (p = 0.002), bone marrow plasma cells ≥ 20% (p &lt; 0.001) and reduction of uninvolved immunoglobulins (p &lt; 0.001). The hemoglobin value, gender, serum albumin, and expression of cyclin D-1 were not of prognostic importance. On multivariate analysis, the percentage of bone marrow plasma cells was the only significant factor predicting progression to MM or AL.

Evaluation of a 5-Color Flow Cytometric Technique for Immunophenotyping and Quantitation of Plasma Cell Myeloma in Post-Therapy Bone Marrows.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 5036-5036
Author(s):  
Tove Isaacson ◽  
Andrzej Jakubowiak ◽  
Lloyd Stoolman ◽  
Usha Kota ◽  
William Finn ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Minimal Residual Disease ◽  
Plasma Cell ◽  
Plasma Cells ◽  
Residual Disease ◽  
Plasma Cell Myeloma ◽  
Color Flow ◽  
Flow Cytometric ◽  
Minimal Residual

Abstract Multiparameter flow cytometry is a useful tool for comprehensive immunophenotyping of plasma cell myeloma, and has been proposed as a sensitive method for the evaluation of minimal residual disease in patients following treatment. This study aimed to assess the value of flow cytometry in quantitation of residual disease, in comparison to routine morphologic examination of first-pull bone marrow aspirate smears, in myeloma patients post-therapy. Heparinized bone marrow aspirates were obtained from 27 treated patients with plasma cell myeloma. Cells were prepared for 5-color flow cytometric analysis within 24-hours of specimen draw. Surface membrane staining with anti-CD19, CD20, CD38, CD45, CD56, and CD138 was followed by ammonium chloride lysis of red cells. Fixed and permeabilized cells were analyzed for cytoplasmic light chains to confirm clonality. Data were acquired using an FC500 flow cytometer (Beckman-Coulter), analyzed with CXP software with plasma cells isolated based on bright CD38+ or CD138+ expression. A median of 97,639 cellular events (range 14,279 to 262,508) were collected per analysis. Flow cytometric enumeration of plasma cells was compared to 500-cell differential counts of Wright-Giemsa-stained first-pull aspirate smears from the same cases. The median plasma cell count as determined by flow cytometry was 0.5% (range 0–7.9%). The median plasma cell count estimated by morphologic review was 8.0% (range 0–84.4%). Flow cytometry underestimated the plasma cell content in all but one case. Clonal plasma cells expressed CD38 and CD138 in all cases; 87.5% (21/24) coexpressed CD56, 25% (6/24) coexpressed CD45, and 4.2% (1/24) coexpressed CD19. None was positive for CD20. Although detection of minimal residual disease after therapy for acute leukemia is routinely achieved by flow cytometric analysis, successful quantitation of minimal residual disease in treated myeloma patients using flow cytometry remains limited as it usually underestimates the plasma cell content of bone marrow samples compared to routine morphology of first-pull aspirates. We have observed that this holds true for both pre-treatment and post-treatment specimens. Causes for the discrepancy may include hemodilution of second-pull aspirates used for flow cytometry, fragility and loss of plasma cells during preparation for flow cytometry, and incomplete disaggregation of plasma cells from bone marrow spicules. With improved outcome of treatments, better and more reliable methods of detection of minimal residual disease are needed for optimal prognostic stratification. We are currently validating alternative methods, which may offer more sensitivity while at the same time allow more objectivity, for assessing the amount of minimal residual disease in myeloma patients.

Comparison Of Hevylite™ Assay and Plasma Cell Immunophenotyping For Response Evaluation and Residual Disease Characterisation In IgA Myeloma

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 5319-5319
Author(s):  
Daniela Lakomy ◽  
Stephanie Lemaire-Ewing ◽  
Cedric Rossi ◽  
Jessica Borgeot ◽  
Jean-Noël Bastie ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Binding Site ◽  
Plasma Cell ◽  
Light Chain ◽  
Plasma Cells ◽  
Conflicts Of Interest ◽  
Residual Disease ◽  
Response To Treatment ◽  
Response Evaluation ◽  
Bone Marrow Plasma

Abstract Introduction The evaluation of multiple myeloma response to treatment as defined by international guidelines is currently based on morphologic examination of bone marrow plasma cells, serum protein electrophoresis (SPEP), immunofixation electrophoresis (IFE) and serum free light chain assay. For several years new tools are available as bone marrow plasma cell immunophenotyping and the HevyliteTM assay. HevyliteTM IgA assay provides an automated evaluation of serum heavy/light chain ratio (HLC) of the involved and uninvolved immunoglobulin (Ig) (i.e. IgAΚ/IgAλ). This is particularly interesting in IgA myeloma where the use of SPEP is limited due to a frequent comigration of monoclonal IgA with other proteins. We therefore compared the IgA quantification by Hevylite™ assay and the bone marrow plasma cell immunophenotyping for response evaluation and residual disease characterisation in IgA myeloma. Methods Hevylite™ assay, SPEP, IFE were performed in eleven IgA myeloma patients at different times: after induction chemotherapy, after the consolidation phase and after autologous stem-cell transplantation (ASCT). In the same time, minimal residual disease (MRD) assessment was performed on bone marrrow by multiparameter flow cytometry (MFC). Hevylite™ assay was performed on a Binding Site SPAplus analyser (Hevylite, Binding Site, Birmingham, UK) following the manufacturer recommendations. SPE and IFE were realized on Sebia Hydrasys analyser (Sebia, Evry, France) and results were read by two experienced biologists. Results 1. We found a perfect agreement between the IFE and immunophenotyping results at each time of evaluation, for positive results as for negative results. 2. The SPEP was contributive only in two patients and in these cases it was less sensitive than IFE. In the other patients, the monoclonal IgA migrated in beta region and/or as multiple bands, making the quantitative estimation difficult. 3. In all patients, when MRD by MFC was undetectable and IFE was negative, the HLC ratio was normal. 4. In 3 patients, HLC ratio was consistent with the IFE and MRD by MFC at each time of evaluation. Nevertheless, in 8 patients out of 11, while HLC ratio became normal, MRD by MFC and IFE were still positive. In all cases, the normalization of HLC ratio was followed, at the next step of evaluation, by the normalization of MFC and IFE. 5. In 5 patients, the normalization of HLC ratio occurred before ASCT, while IFE and MRD by MFC were still positive. Nevertheless, after ASCT, IFE and MRD by MFC became also negative, in accordance with the HLC ratio (Table 1). Conclusions During the evaluation of response to treatment of IgA myeloma, we observed a normalization of HLC ratio (Hevylite™ IgA assay) preceding the normalization of MRD by MFC and IFE. This could be explained by the fact that IFE and immunophenotyping provide very sensitive information but only on the monoclonal component. HLC ratio reflects the balance between the monoclonal and polyclonal Igs of involved and uninvolved isotype. A normalization of HLC ratio can be interpreted as an increasing polyclonal Ig proportion parallel with a decreasing monoclonal Ig proportion and may reflect the reconstitution of polyclonal plasma cells. If confirmed by other studies and long term follow-up, HLC ratio could be a non-invasive predictive marker of a good response in IgA myeloma. Disclosures: No relevant conflicts of interest to declare.

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